1 /*
2 * Copyright (c) 2023, 2026, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "cds/aotMappedHeap.hpp"
26 #include "cds/aotMappedHeapWriter.hpp"
27 #include "cds/aotReferenceObjSupport.hpp"
28 #include "cds/cdsConfig.hpp"
29 #include "cds/filemap.hpp"
30 #include "cds/heapShared.inline.hpp"
31 #include "cds/regeneratedClasses.hpp"
32 #include "classfile/javaClasses.hpp"
33 #include "classfile/modules.hpp"
34 #include "classfile/systemDictionary.hpp"
35 #include "gc/shared/collectedHeap.hpp"
36 #include "memory/allocation.inline.hpp"
37 #include "memory/iterator.inline.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.hpp"
40 #include "oops/compressedOops.hpp"
41 #include "oops/objArrayOop.inline.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/oopHandle.inline.hpp"
44 #include "oops/typeArrayKlass.hpp"
45 #include "oops/typeArrayOop.hpp"
46 #include "runtime/java.hpp"
47 #include "runtime/mutexLocker.hpp"
48 #include "utilities/bitMap.inline.hpp"
49 #if INCLUDE_G1GC
50 #include "gc/g1/g1CollectedHeap.hpp"
51 #include "gc/g1/g1HeapRegion.hpp"
52 #endif
53
54 #if INCLUDE_CDS_JAVA_HEAP
55
56 GrowableArrayCHeap<u1, mtClassShared>* AOTMappedHeapWriter::_buffer = nullptr;
57
58 bool AOTMappedHeapWriter::_is_writing_deterministic_heap = false;
59 size_t AOTMappedHeapWriter::_buffer_used;
60
61 // Heap root segments
62 HeapRootSegments AOTMappedHeapWriter::_heap_root_segments;
63
64 address AOTMappedHeapWriter::_requested_bottom;
65 address AOTMappedHeapWriter::_requested_top;
66
67 GrowableArrayCHeap<AOTMappedHeapWriter::NativePointerInfo, mtClassShared>* AOTMappedHeapWriter::_native_pointers;
68 GrowableArrayCHeap<oop, mtClassShared>* AOTMappedHeapWriter::_source_objs;
69 GrowableArrayCHeap<AOTMappedHeapWriter::HeapObjOrder, mtClassShared>* AOTMappedHeapWriter::_source_objs_order;
70
71 AOTMappedHeapWriter::BufferOffsetToSourceObjectTable*
72 AOTMappedHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
73
74 DumpedInternedStrings *AOTMappedHeapWriter::_dumped_interned_strings = nullptr;
75
76 typedef HashTable<
77 size_t, // offset of a filler from AOTMappedHeapWriter::buffer_bottom()
78 size_t, // size of this filler (in bytes)
79 127, // prime number
80 AnyObj::C_HEAP,
81 mtClassShared> FillersTable;
82 static FillersTable* _fillers;
83 static int _num_native_ptrs = 0;
84
85 void AOTMappedHeapWriter::init() {
86 if (CDSConfig::is_dumping_heap()) {
87 Universe::heap()->collect(GCCause::_java_lang_system_gc);
88
89 _buffer_offset_to_source_obj_table = new (mtClassShared) BufferOffsetToSourceObjectTable(/*size (prime)*/36137, /*max size*/1 * M);
90 _dumped_interned_strings = new (mtClass)DumpedInternedStrings(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE);
91 _fillers = new (mtClassShared) FillersTable();
92 _requested_bottom = nullptr;
93 _requested_top = nullptr;
94
95 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
96 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
97
98 guarantee(MIN_GC_REGION_ALIGNMENT <= G1HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
99
100 if (CDSConfig::old_cds_flags_used()) {
101 // With the old CDS workflow, we can guatantee determninistic output: given
102 // the same classlist file, we can generate the same static CDS archive.
103 // To ensure determinism, we always use the same compressed oop encoding
104 // (zero-based, no shift). See set_requested_address_range().
105 _is_writing_deterministic_heap = true;
106 } else {
107 // Determninistic output is not supported by the new AOT workflow, so
108 // we don't force the (zero-based, no shift) encoding. This way, it is more
109 // likely that we can avoid oop relocation in the production run.
110 _is_writing_deterministic_heap = false;
111 }
112 }
113 }
114
115 // For AOTMappedHeapWriter::narrow_oop_{mode, base, shift}(), see comments
116 // in AOTMappedHeapWriter::set_requested_address_range(),
117 CompressedOops::Mode AOTMappedHeapWriter::narrow_oop_mode() {
118 if (is_writing_deterministic_heap()) {
119 return CompressedOops::UnscaledNarrowOop;
120 } else {
121 return CompressedOops::mode();
122 }
123 }
124
125 address AOTMappedHeapWriter::narrow_oop_base() {
126 if (is_writing_deterministic_heap()) {
127 return nullptr;
128 } else {
129 return CompressedOops::base();
130 }
131 }
132
133 int AOTMappedHeapWriter::narrow_oop_shift() {
134 if (is_writing_deterministic_heap()) {
135 return 0;
136 } else {
137 return CompressedOops::shift();
138 }
139 }
140
141 void AOTMappedHeapWriter::delete_tables_with_raw_oops() {
142 delete _source_objs;
143 _source_objs = nullptr;
144
145 delete _dumped_interned_strings;
146 _dumped_interned_strings = nullptr;
147 }
148
149 void AOTMappedHeapWriter::add_source_obj(oop src_obj) {
150 _source_objs->append(src_obj);
151 }
152
153 void AOTMappedHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
154 AOTMappedHeapInfo* heap_info) {
155 assert(CDSConfig::is_dumping_heap(), "sanity");
156 allocate_buffer();
157 copy_source_objs_to_buffer(roots);
158 set_requested_address_range(heap_info);
159 relocate_embedded_oops(roots, heap_info);
160 }
161
162 bool AOTMappedHeapWriter::is_too_large_to_archive(oop o) {
163 return is_too_large_to_archive(o->size());
164 }
165
166 bool AOTMappedHeapWriter::is_string_too_large_to_archive(oop string) {
167 typeArrayOop value = java_lang_String::value_no_keepalive(string);
168 return is_too_large_to_archive(value);
169 }
170
171 bool AOTMappedHeapWriter::is_too_large_to_archive(size_t size) {
172 assert(size > 0, "no zero-size object");
173 assert(size * HeapWordSize > size, "no overflow");
174 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
175
176 size_t byte_size = size * HeapWordSize;
177 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
178 return true;
179 } else {
180 return false;
181 }
182 }
183
184 // Keep track of the contents of the archived interned string table. This table
185 // is used only by CDSHeapVerifier.
186 void AOTMappedHeapWriter::add_to_dumped_interned_strings(oop string) {
187 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
188 assert(!is_string_too_large_to_archive(string), "must be");
189 bool created;
190 _dumped_interned_strings->put_if_absent(string, true, &created);
191 if (created) {
192 // Prevent string deduplication from changing the value field to
193 // something not in the archive.
194 java_lang_String::set_deduplication_forbidden(string);
195 _dumped_interned_strings->maybe_grow();
196 }
197 }
198
199 bool AOTMappedHeapWriter::is_dumped_interned_string(oop o) {
200 return _dumped_interned_strings->get(o) != nullptr;
201 }
202
203 // Various lookup functions between source_obj, buffered_obj and requested_obj
204 bool AOTMappedHeapWriter::is_in_requested_range(oop o) {
205 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
206 address a = cast_from_oop<address>(o);
207 return (_requested_bottom <= a && a < _requested_top);
208 }
209
210 oop AOTMappedHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
211 oop req_obj = cast_to_oop(_requested_bottom + offset);
212 assert(is_in_requested_range(req_obj), "must be");
213 return req_obj;
214 }
215
216 oop AOTMappedHeapWriter::source_obj_to_requested_obj(oop src_obj) {
217 assert(CDSConfig::is_dumping_heap(), "dump-time only");
218 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
219 if (p != nullptr) {
220 return requested_obj_from_buffer_offset(p->buffer_offset());
221 } else {
222 return nullptr;
223 }
224 }
225
226 oop AOTMappedHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
227 OopHandle* oh = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
228 if (oh != nullptr) {
229 return oh->resolve();
230 } else {
231 return nullptr;
232 }
233 }
234
235 Klass* AOTMappedHeapWriter::real_klass_of_buffered_oop(address buffered_addr) {
236 oop p = buffered_addr_to_source_obj(buffered_addr);
237 if (p != nullptr) {
238 return p->klass();
239 } else if (get_filler_size_at(buffered_addr) > 0) {
240 return Universe::fillerArrayKlass();
241 } else {
242 // This is one of the root segments
243 return Universe::objectArrayKlass();
244 }
245 }
246
247 size_t AOTMappedHeapWriter::size_of_buffered_oop(address buffered_addr) {
248 oop p = buffered_addr_to_source_obj(buffered_addr);
249 if (p != nullptr) {
250 return p->size();
251 }
252
253 size_t nbytes = get_filler_size_at(buffered_addr);
254 if (nbytes > 0) {
255 assert((nbytes % BytesPerWord) == 0, "should be aligned");
256 return nbytes / BytesPerWord;
257 }
258
259 address hrs = buffer_bottom();
260 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
261 nbytes = _heap_root_segments.size_in_bytes(seg_idx);
262 if (hrs == buffered_addr) {
263 assert((nbytes % BytesPerWord) == 0, "should be aligned");
264 return nbytes / BytesPerWord;
265 }
266 hrs += nbytes;
267 }
268
269 ShouldNotReachHere();
270 return 0;
271 }
272
273 address AOTMappedHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
274 return _requested_bottom + buffered_address_to_offset(buffered_addr);
275 }
276
277 address AOTMappedHeapWriter::requested_address() {
278 assert(_buffer != nullptr, "must be initialized");
279 return _requested_bottom;
280 }
281
282 void AOTMappedHeapWriter::allocate_buffer() {
283 int initial_buffer_size = 100000;
284 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
285 _buffer_used = 0;
286 ensure_buffer_space(1); // so that buffer_bottom() works
287 }
288
289 void AOTMappedHeapWriter::ensure_buffer_space(size_t min_bytes) {
290 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
291 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
292 _buffer->at_grow(to_array_index(min_bytes));
293 }
294
295 objArrayOop AOTMappedHeapWriter::allocate_root_segment(size_t offset, int element_count) {
296 HeapWord* mem = offset_to_buffered_address<HeapWord *>(offset);
297 memset(mem, 0, objArrayOopDesc::object_size(element_count));
298
299 // The initialization code is copied from MemAllocator::finish and ObjArrayAllocator::initialize.
300 if (UseCompactObjectHeaders) {
301 oopDesc::release_set_mark(mem, Universe::objectArrayKlass()->prototype_header());
302 } else {
303 oopDesc::set_mark(mem, markWord::prototype());
304 oopDesc::release_set_klass(mem, Universe::objectArrayKlass());
305 }
306 arrayOopDesc::set_length(mem, element_count);
307 return objArrayOop(cast_to_oop(mem));
308 }
309
310 void AOTMappedHeapWriter::root_segment_at_put(objArrayOop segment, int index, oop root) {
311 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside the real heap!
312 if (UseCompressedOops) {
313 *segment->obj_at_addr<narrowOop>(index) = CompressedOops::encode(root);
314 } else {
315 *segment->obj_at_addr<oop>(index) = root;
316 }
317 }
318
319 void AOTMappedHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
320 // Depending on the number of classes we are archiving, a single roots array may be
321 // larger than MIN_GC_REGION_ALIGNMENT. Roots are allocated first in the buffer, which
322 // allows us to chop the large array into a series of "segments". Current layout
323 // starts with zero or more segments exactly fitting MIN_GC_REGION_ALIGNMENT, and end
324 // with a single segment that may be smaller than MIN_GC_REGION_ALIGNMENT.
325 // This is simple and efficient. We do not need filler objects anywhere between the segments,
326 // or immediately after the last segment. This allows starting the object dump immediately
327 // after the roots.
328
329 assert((_buffer_used % MIN_GC_REGION_ALIGNMENT) == 0,
330 "Pre-condition: Roots start at aligned boundary: %zu", _buffer_used);
331
332 int max_elem_count = ((MIN_GC_REGION_ALIGNMENT - arrayOopDesc::header_size_in_bytes()) / heapOopSize);
333 assert(objArrayOopDesc::object_size(max_elem_count)*HeapWordSize == MIN_GC_REGION_ALIGNMENT,
334 "Should match exactly");
335
336 HeapRootSegments segments(_buffer_used,
337 roots->length(),
338 MIN_GC_REGION_ALIGNMENT,
339 max_elem_count);
340
341 int root_index = 0;
342 for (size_t seg_idx = 0; seg_idx < segments.count(); seg_idx++) {
343 int size_elems = segments.size_in_elems(seg_idx);
344 size_t size_bytes = segments.size_in_bytes(seg_idx);
345
346 size_t oop_offset = _buffer_used;
347 _buffer_used = oop_offset + size_bytes;
348 ensure_buffer_space(_buffer_used);
349
350 assert((oop_offset % MIN_GC_REGION_ALIGNMENT) == 0,
351 "Roots segment %zu start is not aligned: %zu",
352 segments.count(), oop_offset);
353
354 objArrayOop seg_oop = allocate_root_segment(oop_offset, size_elems);
355 for (int i = 0; i < size_elems; i++) {
356 root_segment_at_put(seg_oop, i, roots->at(root_index++));
357 }
358
359 log_info(aot, heap)("archived obj root segment [%d] = %zu bytes, obj = " PTR_FORMAT,
360 size_elems, size_bytes, p2i(seg_oop));
361 }
362
363 assert(root_index == roots->length(), "Post-condition: All roots are handled");
364
365 _heap_root_segments = segments;
366 }
367
368 // The goal is to sort the objects in increasing order of:
369 // - objects that have only oop pointers
370 // - objects that have both native and oop pointers
371 // - objects that have only native pointers
372 // - objects that have no pointers
373 static int oop_sorting_rank(oop o) {
374 bool has_oop_ptr, has_native_ptr;
375 HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
376
377 if (has_oop_ptr) {
378 if (!has_native_ptr) {
379 return 0;
380 } else {
381 return 1;
382 }
383 } else {
384 if (has_native_ptr) {
385 return 2;
386 } else {
387 return 3;
388 }
389 }
390 }
391
392 int AOTMappedHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
393 int rank_a = a->_rank;
394 int rank_b = b->_rank;
395
396 if (rank_a != rank_b) {
397 return rank_a - rank_b;
398 } else {
399 // If they are the same rank, sort them by their position in the _source_objs array
400 return a->_index - b->_index;
401 }
402 }
403
404 void AOTMappedHeapWriter::sort_source_objs() {
405 log_info(aot)("sorting heap objects");
406 int len = _source_objs->length();
407 _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
408
409 for (int i = 0; i < len; i++) {
410 oop o = _source_objs->at(i);
411 int rank = oop_sorting_rank(o);
412 HeapObjOrder os = {i, rank};
413 _source_objs_order->append(os);
414 }
415 log_info(aot)("computed ranks");
416 _source_objs_order->sort(compare_objs_by_oop_fields);
417 log_info(aot)("sorting heap objects done");
418 }
419
420 void AOTMappedHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
421 // There could be multiple root segments, which we want to be aligned by region.
422 // Putting them ahead of objects makes sure we waste no space.
423 copy_roots_to_buffer(roots);
424
425 sort_source_objs();
426 for (int i = 0; i < _source_objs_order->length(); i++) {
427 int src_obj_index = _source_objs_order->at(i)._index;
428 oop src_obj = _source_objs->at(src_obj_index);
429 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
430 assert(info != nullptr, "must be");
431 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
432 info->set_buffer_offset(buffer_offset);
433
434 OopHandle handle(Universe::vm_global(), src_obj);
435 _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, handle);
436 _buffer_offset_to_source_obj_table->maybe_grow();
437
438 if (java_lang_Module::is_instance(src_obj)) {
439 Modules::check_archived_module_oop(src_obj);
440 }
441 }
442
443 log_info(aot)("Size of heap region = %zu bytes, %d objects, %d roots, %d native ptrs",
444 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
445 }
446
447 size_t AOTMappedHeapWriter::filler_array_byte_size(int length) {
448 size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
449 return byte_size;
450 }
451
452 int AOTMappedHeapWriter::filler_array_length(size_t fill_bytes) {
453 assert(is_object_aligned(fill_bytes), "must be");
454 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
455
456 int initial_length = to_array_length(fill_bytes / elemSize);
457 for (int length = initial_length; length >= 0; length --) {
458 size_t array_byte_size = filler_array_byte_size(length);
459 if (array_byte_size == fill_bytes) {
460 return length;
461 }
462 }
463
464 ShouldNotReachHere();
465 return -1;
466 }
467
468 HeapWord* AOTMappedHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
469 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
470 Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
471 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
472 memset(mem, 0, fill_bytes);
473 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
474 if (UseCompactObjectHeaders) {
475 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
476 } else {
477 oopDesc::set_mark(mem, markWord::prototype());
478 cast_to_oop(mem)->set_narrow_klass(nk);
479 }
480 arrayOopDesc::set_length(mem, array_length);
481 return mem;
482 }
483
484 void AOTMappedHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
485 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
486 // leftover space is smaller than a zero-sized array object). Therefore, we need to
487 // make sure there's enough space of min_filler_byte_size in the current region after
488 // required_byte_size has been allocated. If not, fill the remainder of the current
489 // region.
490 size_t min_filler_byte_size = filler_array_byte_size(0);
491 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
492
493 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
494 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
495
496 if (cur_min_region_bottom != next_min_region_bottom) {
497 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
498 // we can map the region in any region-based collector.
499 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
500 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
501 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
502
503 const size_t filler_end = next_min_region_bottom;
504 const size_t fill_bytes = filler_end - _buffer_used;
505 assert(fill_bytes > 0, "must be");
506 ensure_buffer_space(filler_end);
507
508 int array_length = filler_array_length(fill_bytes);
509 log_info(aot, heap)("Inserting filler obj array of %d elements (%zu bytes total) @ buffer offset %zu",
510 array_length, fill_bytes, _buffer_used);
511 HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
512 _buffer_used = filler_end;
513 _fillers->put(buffered_address_to_offset((address)filler), fill_bytes);
514 }
515 }
516
517 size_t AOTMappedHeapWriter::get_filler_size_at(address buffered_addr) {
518 size_t* p = _fillers->get(buffered_address_to_offset(buffered_addr));
519 if (p != nullptr) {
520 assert(*p > 0, "filler must be larger than zero bytes");
521 return *p;
522 } else {
523 return 0; // buffered_addr is not a filler
524 }
525 }
526
527 template <typename T>
528 void update_buffered_object_field(address buffered_obj, int field_offset, T value) {
529 T* field_addr = cast_to_oop(buffered_obj)->field_addr<T>(field_offset);
530 *field_addr = value;
531 }
532
533 size_t AOTMappedHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
534 assert(!is_too_large_to_archive(src_obj), "already checked");
535 size_t byte_size = src_obj->size() * HeapWordSize;
536 assert(byte_size > 0, "no zero-size objects");
537
538 // For region-based collectors such as G1, the archive heap may be mapped into
539 // multiple regions. We need to make sure that we don't have an object that can possible
540 // span across two regions.
541 maybe_fill_gc_region_gap(byte_size);
542
543 size_t new_used = _buffer_used + byte_size;
544 assert(new_used > _buffer_used, "no wrap around");
545
546 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
547 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
548 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
549
550 ensure_buffer_space(new_used);
551
552 address from = cast_from_oop<address>(src_obj);
553 address to = offset_to_buffered_address<address>(_buffer_used);
554 assert(is_object_aligned(_buffer_used), "sanity");
555 assert(is_object_aligned(byte_size), "sanity");
556 memcpy(to, from, byte_size);
557
558 // These native pointers will be restored explicitly at run time.
559 if (java_lang_Module::is_instance(src_obj)) {
560 update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
561 } else if (java_lang_ClassLoader::is_instance(src_obj)) {
562 #ifdef ASSERT
563 // We only archive these loaders
564 if (src_obj != SystemDictionary::java_platform_loader() &&
565 src_obj != SystemDictionary::java_system_loader()) {
566 assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
567 }
568 #endif
569 update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
570 }
571
572 size_t buffered_obj_offset = _buffer_used;
573 _buffer_used = new_used;
574
575 return buffered_obj_offset;
576 }
577
578 // Set the range [_requested_bottom, _requested_top), the requested address range of all
579 // the archived heap objects in the production run.
580 //
581 // (1) UseCompressedOops == true && !is_writing_deterministic_heap()
582 //
583 // The archived objects are stored using the COOPS encoding of the assembly phase.
584 // We pick a range within the heap used by the assembly phase.
585 //
586 // In the production run, if different COOPS encodings are used:
587 // - The heap contents needs to be relocated.
588 //
589 // (2) UseCompressedOops == true && is_writing_deterministic_heap()
590 //
591 // We always use zero-based, zero-shift encoding. _requested_top is aligned to 0x10000000.
592 //
593 // (3) UseCompressedOops == false:
594 //
595 // In the production run, the heap range is usually picked (randomly) by the OS, so we
596 // will almost always need to perform relocation, regardless of how we pick the requested
597 // address range.
598 //
599 // So we just hard code it to NOCOOPS_REQUESTED_BASE.
600 //
601 void AOTMappedHeapWriter::set_requested_address_range(AOTMappedHeapInfo* info) {
602 assert(!info->is_used(), "only set once");
603
604 size_t heap_region_byte_size = _buffer_used;
605 assert(heap_region_byte_size > 0, "must archived at least one object!");
606
607 if (UseCompressedOops) {
608 if (is_writing_deterministic_heap()) {
609 // Pick a heap range so that requested addresses can be encoded with zero-base/no shift.
610 // We align the requested bottom to at least 1 MB: if the production run uses G1 with a small
611 // heap (e.g., -Xmx256m), it's likely that we can map the archived objects at the
612 // requested location to avoid relocation.
613 //
614 // For other collectors or larger heaps, relocation is unavoidable, but is usually
615 // quite cheap. If you really want to avoid relocation, use the AOT workflow instead.
616 address heap_end = (address)0x100000000;
617 size_t alignment = MAX2(MIN_GC_REGION_ALIGNMENT, 1024 * 1024);
618 if (align_up(heap_region_byte_size, alignment) >= (size_t)heap_end) {
619 log_error(aot, heap)("cached heap space is too large: %zu bytes", heap_region_byte_size);
620 AOTMetaspace::unrecoverable_writing_error();
621 }
622 _requested_bottom = align_down(heap_end - heap_region_byte_size, alignment);
623 } else if (UseG1GC) {
624 // For G1, pick the range at the top of the current heap. If the exact same heap sizes
625 // are used in the production run, it's likely that we can map the archived objects
626 // at the requested location to avoid relocation.
627 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
628 log_info(aot, heap)("Heap end = %p", heap_end);
629 _requested_bottom = align_down(heap_end - heap_region_byte_size, G1HeapRegion::GrainBytes);
630 _requested_bottom = align_down(_requested_bottom, MIN_GC_REGION_ALIGNMENT);
631 assert(is_aligned(_requested_bottom, G1HeapRegion::GrainBytes), "sanity");
632 } else {
633 _requested_bottom = align_up(CompressedOops::begin(), MIN_GC_REGION_ALIGNMENT);
634 }
635 } else {
636 // We always write the objects as if the heap started at this address. This
637 // makes the contents of the archive heap deterministic.
638 //
639 // Note that at runtime, the heap address is selected by the OS, so the archive
640 // heap will not be mapped at 0x10000000, and the contents need to be patched.
641 _requested_bottom = align_up((address)NOCOOPS_REQUESTED_BASE, MIN_GC_REGION_ALIGNMENT);
642 }
643
644 assert(is_aligned(_requested_bottom, MIN_GC_REGION_ALIGNMENT), "sanity");
645
646 _requested_top = _requested_bottom + _buffer_used;
647
648 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
649 offset_to_buffered_address<HeapWord*>(_buffer_used)));
650 info->set_root_segments(_heap_root_segments);
651 }
652
653 // Oop relocation
654
655 template <typename T> T* AOTMappedHeapWriter::requested_addr_to_buffered_addr(T* p) {
656 assert(is_in_requested_range(cast_to_oop(p)), "must be");
657
658 address addr = address(p);
659 assert(addr >= _requested_bottom, "must be");
660 size_t offset = addr - _requested_bottom;
661 return offset_to_buffered_address<T*>(offset);
662 }
663
664 template <typename T> oop AOTMappedHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
665 oop o = load_oop_from_buffer(buffered_addr);
666 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
667 return o;
668 }
669
670 template <typename T> void AOTMappedHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
671 oop request_oop) {
672 assert(request_oop == nullptr || is_in_requested_range(request_oop), "must be");
673 store_oop_in_buffer(buffered_addr, request_oop);
674 }
675
676 inline void AOTMappedHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
677 *buffered_addr = requested_obj;
678 }
679
680 inline void AOTMappedHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
681 narrowOop val = CompressedOops::encode(requested_obj);
682 *buffered_addr = val;
683 }
684
685 oop AOTMappedHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
686 return *buffered_addr;
687 }
688
689 oop AOTMappedHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
690 return CompressedOops::decode(*buffered_addr);
691 }
692
693 template <typename T> void AOTMappedHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, oop source_referent, CHeapBitMap* oopmap) {
694 oop request_referent = source_obj_to_requested_obj(source_referent);
695 if (UseCompressedOops && is_writing_deterministic_heap()) {
696 // We use zero-based, 0-shift encoding, so the narrowOop is just the lower
697 // 32 bits of request_referent
698 intptr_t addr = cast_from_oop<intptr_t>(request_referent);
699 *((narrowOop*)field_addr_in_buffer) = CompressedOops::narrow_oop_cast(addr);
700 } else {
701 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
702 }
703 if (request_referent != nullptr) {
704 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
705 }
706 }
707
708 template <typename T> void AOTMappedHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
709 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
710 address requested_region_bottom;
711
712 assert(request_p >= (T*)_requested_bottom, "sanity");
713 assert(request_p < (T*)_requested_top, "sanity");
714 requested_region_bottom = _requested_bottom;
715
716 // Mark the pointer in the oopmap
717 T* region_bottom = (T*)requested_region_bottom;
718 assert(request_p >= region_bottom, "must be");
719 BitMap::idx_t idx = request_p - region_bottom;
720 assert(idx < oopmap->size(), "overflow");
721 oopmap->set_bit(idx);
722 }
723
724 void AOTMappedHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
725 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
726 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
727 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
728
729 oop fake_oop = cast_to_oop(buffered_addr);
730 if (UseCompactObjectHeaders) {
731 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk));
732 } else {
733 fake_oop->set_narrow_klass(nk);
734 }
735
736 if (src_obj == nullptr) {
737 return;
738 }
739 // We need to retain the identity_hash, because it may have been used by some hashtables
740 // in the shared heap.
741 if (!src_obj->fast_no_hash_check()) {
742 intptr_t src_hash = src_obj->identity_hash();
743 if (UseCompactObjectHeaders) {
744 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
745 } else {
746 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
747 }
748 assert(fake_oop->mark().is_unlocked(), "sanity");
749
750 DEBUG_ONLY(intptr_t archived_hash = fake_oop->identity_hash());
751 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
752 }
753 // Strip age bits.
754 fake_oop->set_mark(fake_oop->mark().set_age(0));
755 }
756
757 class AOTMappedHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
758 oop _src_obj;
759 address _buffered_obj;
760 CHeapBitMap* _oopmap;
761 bool _is_java_lang_ref;
762 public:
763 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
764 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap)
765 {
766 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(src_obj);
767 }
768
769 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
770 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
771
772 private:
773 template <class T> void do_oop_work(T *p) {
774 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_src_obj));
775 T* field_addr = (T*)(_buffered_obj + field_offset);
776 oop referent = load_source_oop_from_buffer<T>(field_addr);
777 referent = HeapShared::maybe_remap_referent(_is_java_lang_ref, field_offset, referent);
778 AOTMappedHeapWriter::relocate_field_in_buffer<T>(field_addr, referent, _oopmap);
779 }
780 };
781
782 static void log_bitmap_usage(const char* which, BitMap* bitmap, size_t total_bits) {
783 // The whole heap is covered by total_bits, but there are only non-zero bits within [start ... end).
784 size_t start = bitmap->find_first_set_bit(0);
785 size_t end = bitmap->size();
786 log_info(aot)("%s = %7zu ... %7zu (%3zu%% ... %3zu%% = %3zu%%)", which,
787 start, end,
788 start * 100 / total_bits,
789 end * 100 / total_bits,
790 (end - start) * 100 / total_bits);
791 }
792
793 // Update all oop fields embedded in the buffered objects
794 void AOTMappedHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
795 AOTMappedHeapInfo* heap_info) {
796 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
797 size_t heap_region_byte_size = _buffer_used;
798 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
799
800 for (int i = 0; i < _source_objs_order->length(); i++) {
801 int src_obj_index = _source_objs_order->at(i)._index;
802 oop src_obj = _source_objs->at(src_obj_index);
803 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
804 assert(info != nullptr, "must be");
805 oop requested_obj = requested_obj_from_buffer_offset(info->buffer_offset());
806 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
807 address buffered_obj = offset_to_buffered_address<address>(info->buffer_offset());
808 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
809 src_obj->oop_iterate(&relocator);
810 mark_native_pointers(src_obj);
811 };
812
813 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
814 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
815 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
816 size_t seg_offset = _heap_root_segments.segment_offset(seg_idx);
817
818 objArrayOop requested_obj = (objArrayOop)requested_obj_from_buffer_offset(seg_offset);
819 update_header_for_requested_obj(requested_obj, nullptr, Universe::objectArrayKlass());
820 address buffered_obj = offset_to_buffered_address<address>(seg_offset);
821 int length = _heap_root_segments.size_in_elems(seg_idx);
822
823 size_t elem_size = UseCompressedOops ? sizeof(narrowOop) : sizeof(oop);
824
825 for (int i = 0; i < length; i++) {
826 // There is no source object; these are native oops - load, translate and
827 // write back
828 size_t elem_offset = objArrayOopDesc::base_offset_in_bytes() + elem_size * i;
829 HeapWord* elem_addr = (HeapWord*)(buffered_obj + elem_offset);
830 oop obj = NativeAccess<>::oop_load(elem_addr);
831 obj = HeapShared::maybe_remap_referent(false /* is_reference_field */, elem_offset, obj);
832 if (UseCompressedOops) {
833 relocate_field_in_buffer<narrowOop>((narrowOop*)elem_addr, obj, heap_info->oopmap());
834 } else {
835 relocate_field_in_buffer<oop>((oop*)elem_addr, obj, heap_info->oopmap());
836 }
837 }
838 }
839
840 compute_ptrmap(heap_info);
841
842 size_t total_bytes = (size_t)_buffer->length();
843 log_bitmap_usage("oopmap", heap_info->oopmap(), total_bytes / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop)));
844 log_bitmap_usage("ptrmap", heap_info->ptrmap(), total_bytes / sizeof(address));
845 }
846
847 void AOTMappedHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
848 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
849 if (ptr != nullptr) {
850 NativePointerInfo info;
851 info._src_obj = src_obj;
852 info._field_offset = field_offset;
853 _native_pointers->append(info);
854 HeapShared::set_has_native_pointers(src_obj);
855 _num_native_ptrs ++;
856 }
857 }
858
859 void AOTMappedHeapWriter::mark_native_pointers(oop orig_obj) {
860 HeapShared::do_metadata_offsets(orig_obj, [&](int offset) {
861 mark_native_pointer(orig_obj, offset);
862 });
863 }
864
865 void AOTMappedHeapWriter::compute_ptrmap(AOTMappedHeapInfo* heap_info) {
866 int num_non_null_ptrs = 0;
867 Metadata** bottom = (Metadata**) _requested_bottom;
868 Metadata** top = (Metadata**) _requested_top; // exclusive
869 heap_info->ptrmap()->resize(top - bottom);
870
871 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
872 for (int i = 0; i < _native_pointers->length(); i++) {
873 NativePointerInfo info = _native_pointers->at(i);
874 oop src_obj = info._src_obj;
875 int field_offset = info._field_offset;
876 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
877 // requested_field_addr = the address of this field in the requested space
878 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
879 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
880 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
881
882 // Mark this field in the bitmap
883 BitMap::idx_t idx = requested_field_addr - bottom;
884 heap_info->ptrmap()->set_bit(idx);
885 num_non_null_ptrs ++;
886 max_idx = MAX2(max_idx, idx);
887
888 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
889 // this address if the RO/RW regions are mapped at the default location).
890
891 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
892 Metadata* native_ptr = *buffered_field_addr;
893 guarantee(native_ptr != nullptr, "sanity");
894
895 if (RegeneratedClasses::has_been_regenerated(native_ptr)) {
896 native_ptr = RegeneratedClasses::get_regenerated_object(native_ptr);
897 }
898
899 guarantee(ArchiveBuilder::current()->has_been_archived((address)native_ptr),
900 "Metadata %p should have been archived", native_ptr);
901
902 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
903 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
904 *buffered_field_addr = (Metadata*)requested_native_ptr;
905 }
906
907 heap_info->ptrmap()->resize(max_idx + 1);
908 log_info(aot, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (%zu bits)",
909 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
910 }
911
912 AOTMapLogger::OopDataIterator* AOTMappedHeapWriter::oop_iterator(AOTMappedHeapInfo* heap_info) {
913 class MappedWriterOopIterator : public AOTMappedHeapOopIterator {
914 public:
915 MappedWriterOopIterator(address buffer_start,
916 address buffer_end,
917 address requested_base,
918 address requested_start,
919 int requested_shift,
920 size_t num_root_segments) :
921 AOTMappedHeapOopIterator(buffer_start,
922 buffer_end,
923 requested_base,
924 requested_start,
925 requested_shift,
926 num_root_segments) {}
927
928 AOTMapLogger::OopData capture(address buffered_addr) override {
929 oopDesc* raw_oop = (oopDesc*)buffered_addr;
930 size_t size = size_of_buffered_oop(buffered_addr);
931 address requested_addr = buffered_addr_to_requested_addr(buffered_addr);
932 intptr_t target_location = (intptr_t)requested_addr;
933 uint64_t pd = (uint64_t)(pointer_delta(buffered_addr, _buffer_start, 1));
934 uint32_t narrow_location = checked_cast<uint32_t>(_buffer_start_narrow_oop + (pd >> _requested_shift));
935 Klass* klass = real_klass_of_buffered_oop(buffered_addr);
936
937 return { buffered_addr,
938 requested_addr,
939 target_location,
940 narrow_location,
941 raw_oop,
942 klass,
943 size,
944 false };
945 }
946 };
947
948 MemRegion r = heap_info->buffer_region();
949 address buffer_start = address(r.start());
950 address buffer_end = address(r.end());
951
952 address requested_base = UseCompressedOops ? AOTMappedHeapWriter::narrow_oop_base() : (address)AOTMappedHeapWriter::NOCOOPS_REQUESTED_BASE;
953 address requested_start = UseCompressedOops ? AOTMappedHeapWriter::buffered_addr_to_requested_addr(buffer_start) : requested_base;
954 int requested_shift = AOTMappedHeapWriter::narrow_oop_shift();
955
956 return new MappedWriterOopIterator(buffer_start,
957 buffer_end,
958 requested_base,
959 requested_start,
960 requested_shift,
961 heap_info->root_segments().count());
962 }
963
964 #endif // INCLUDE_CDS_JAVA_HEAP